Hi Lucy and rocknbil,
Thanks for helping me out with my problem. I was able to solve my problem. It turns out that it was being caused by a plugin that I installed months ago. In case someone else also encounters this, the name of the plugin is WinkPress Affiliate Links Manager. Maybe I didn't configure it correctly or it's not compatible with the version of my wordpress. But I'm happy that this has been fixed.
Thanks again for your help and sorry if I violated any policies here.